The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art to the presently claimed inventions, or relevant, nor that any of the publications specifically or implicitly referenced are prior art.
The exendins are peptides that are found in the salivary secretions of the Gila monster and the Mexican Beaded Lizard, reptiles that are indigenous to Arizona and Northern Mexico. Exendin-3 [SEQ ID. NO. 1: His Ser Asp Gly Thr Phe Thr Ser Asp Leu Ser Lys Gln Met Glu Glu Glu Ala Val Arg Leu Phe Ile Glu Trp Leu Lys Asn Gly Gly Pro Ser Ser Gly Ala Pro Pro Pro Ser-NH2] is present in the salivary secretions of Heloderma a horridum (Mexican Beaded Lizard), and exendin-4 [SEQ. ID. NO. 2: His Gly Glu Gly Thr Phe Thr Ser Asp Leu Ser Lys Gln Met Glu Glu Glu Ala Val Arg Leu Phe Ile Glu Trp Leu Lys Asn Gly Gly Pro Ser Ser Gly Ala Pro Pro Pro Ser-NH2] is present in the salivary secretions of Heloderma suspectum (Gila monster)(Eng, J., et al., J. Biol. Chem., 265:20259-62, 1990; Eng, J., et al., J. Biol. Chem., 267:7402-05, 1992). The amino acid sequence of exendin-3 is shown in FIG. 1. The amino acid sequence of exendin-4 is shown in FIG. 2. Exendin-4 was first thought to be a (potentially toxic) component of the venom. It now appears that exendin-4 is devoid of toxicity, and that it instead is made in salivary glands in the Gila monster.
The exendins have some sequence similarity to several members of the glucagon-like peptide family, with the highest homology, 53%, being to GLP-1 [7-36]NH2 [SEQ ID NO. 189] (Goke, et al., J. Biol. Chem., 268:19650-55, 1993). GLP-1 [7-36] NH2 is also known as proglucagon [78-107], or simply “GLP-1” as used most often herein. GLP-1 has an insulinotropic effect, stimulating insulin secretion from pancreatic beta cells. GLP-1 has also been reported to inhibit glucagon secretion from pancreatic alpha-cells (∅rsov, et al., Diabetes, 42:658-61, 1993; D'Alessio, et al., J. Clin. Invest., 97:133-38, 1996). The amino acid sequence of GLP-I is shown in FIG. 3. GLP-1 has been reported to inhibit gastric emptying (Willms B, et al., J Clin Endocrinol Metab 81 (1): 327-32, 1996; Wettergren A, et al., Dig Dis Sci 38 (4): 665-73, 1993), and gastric acid secretion (Schjoldager BT, et al., Dig Dis Sci 34 (5): 703-8, 1989; O'Halloran DJ, et al., J Endocrinol 126 (1): 169-73, 1990; Wettergren A, et al, Dig Dis Sci 38 (4): 665-73, 1993)). GLP-1[7-37], which has an additional glycine residue at its carboxy terminus, also stimulates insulin secretion in humans (∅rsov, et al., Diabetes, 42: 658-61, 1993). A transmembrane G-protein adenylate-cyclase-coupled receptor said to be responsible at least in part for the insulinotropic effect of GLP-1 has reportedly been cloned from a beta-cell line (Thorens, Proc. Natl. Acad. Sci. USA 89: 8641-45, 1992).
GLP-1 has been the focus of significant investigation in recent years due to reported actions such as the amplification of stimulated insulin production (Byrne M M, Goke B. Lessons from human studies with glucagon-like peptide-1: Potential of the gut hormone for clinical use. In: Fehmann H C, Goke B. Insulinotropic Gut Hormone Glucagon-Like Peptide 1. Basel, Switzerland: Karger, 1997:219-33), the inhibition of gastric emptying (Wettergren A, et al., Truncated GLP-1 (proglucagon 78-107-amide) inhibits gastric and pancreatic functions in man, Dig. Dis. Sci. 1993 April; 38 (4): 665-73), the inhibition of glucagon secretion (Creutzfeldt WOC, et al., Glucagonostatic actions and reduction of fasting hyperglycemia by exogenous glucagon-like peptide I(7-36) amide in type I diabetic patients, Diabetes Care 1996;19(6):580-6), and a purported role in appetite control (Turton M D, et al., A role for glucagon-like peptide-1 in the central regulation of feeding, Nature 1996 January; 379(6560):69-72). GLP-1 has also been reported to restore islet glucose sensitivity in aging rats, restoring their glucose tolerance to that of younger rats (Egan J M, et al., Glucagon-like peptide-1 restores acute-phase insulin release to aged rats, Diabetologia 1997 June 40(Suppl 1):A130). The short duration of biological action of GLP-1 in vivo is one feature of the peptide that has hampered its development as a therapeutic agent.
Pharmacological studies have demonstrated both similarities and differences between exendin-4 and GLP-1. Exendin-4 reportedly can act at GLP-1 receptors on insulin-secreting βTC1 cells, at dispersed acinar cells from guinea pig pancreas, and at parietal cells from stomach. The peptide is also reported to stimulate somatostatin release and inhibit gastrin release in isolated stomachs (Goke, et al., J. Biol. Chem. 268:19650-55, 1993; Schepp, et al., Eur. J. Pharmacol., 69:183-91, 1994; Eissele, et al., Life Sci., 55:629-34, 1994). Exendin-3 and exendin-4 were reportedly found to stimulate CAMP production in, and amylase release from, pancreatic acinar cells (Malhotra, R., et al., Regulatory Peptides, 41:149-56, 1992; Raufman, et al., J. Biol. Chem. 267;21432-37, 1992; Singh, et al., Regul. Pent. 53:47-59, 1994). Exendin-4 also has a significantly longer duration of action than GLP-1. For example, in one experiment, glucose lowering by exendin-4 in diabetic mice was reported to persist for several hours, and, depending on dose, for up to 24 hours (Eng J. Prolonged effect of exendin-4 on hyperglycemia of db/db mice, Diabetes 1996 May; 45(Suppl 2):152A (abstract 554)). Based on their insulinotropic activities, the use of exendin-3 and exendin-4 for the treatment of diabetes mellitus and the prevention of hyperglycemia has been proposed (Eng, U.S. Pat. No. 5,424,286).
C-terminally truncated exendin peptides such as exendin-4[9-39], a carboxyamidated molecule, and fragments 3-39 through 9-39 have been reported to be potent and selective antagonists of GLP-1 (Goke, et al., J. Biol. Chem., 268:19650-55, 1993; Raufman, J. P., et al., J. Biol. Chem. 266:2897-902, 1991; Schepp, W., et al., Eur. J. Pharm. 269:183-91, 1994; Montrose-Rafizadeh, et al., Diabetes, 45(Suppl. 2):152A, 1996). Exendin-4[9-39] is said to block endogenous GLP-1 in vivo, resulting in reduced insulin secretion. Wang, et al., J. Clin. Invest., 95:417-21, 1995; D'Alessio, et al., J. Clin. Invest., 97:133-38, 1996). A receptor apparently responsible for the insulinotropic effect of GLP-1 in rats has reportedly been cloned from rat pancreatic islet cell (Thorens, B., Proc. Natl. Acad. Sci. USA 89:8641-8645, 1992). Exendins and exendin-4[9-39] are said to bind to the cloned rat GLP-1 receptor (rat pancreatic β-cell GLP-1 receptor (Fehmann HC, et al., Peptides 15 (3): 453-6, 1994) and human GLP-1 receptor (Thorens B, et al., Diabetes 42 (11): 1678-82, 1993)). In cells transfected with the cloned GLP-1 receptor, exendin-4 is reportedly an agonist, i.e., it increases cAMP, while exendin [9-39] is identified as an antagonist, i.e., it blocks the stimulatory actions of exendin-4 and GLP-1. Id.
Exendin-4 [9-39] is also reported to act as an antagonist of the full length exendins, inhibiting stimulation of pancreatic acinar cells by exendin-3 and exendin-4 (Raufman, et al., J. Biol. Chem. 266:2897-902, 1991; Raufman, et al., J. Biol. Chem., 266:21432-37, 1992). It is also reported that exendin [9-39] inhibits the stimulation of plasma insulin levels by exendin-4, and inhibits the somatostatin release-stimulating and gastrin release-inhibiting activities of exendin-4 and GLP-1 (Kolligs, F., et al., Diabetes, 44:16-19, 1995; Eissele, et al., Life Sciences, 55:629-34, 1994). Exendin [9-39] has been used to investigate the physiological relevance of central GLP-1 in control of food intake (Turton, M. D. et al. Nature 379:69-72, 1996). GLP-1 administered by intracerebroventricular (ICV) injection inhibits food intake in rats. This satiety-inducing effect of GLP-1 delivered ICV is reported to be inhibited by ICV injection of exendin [9-39] (Turton, supra). However, it has been reported that GLP-1 does not inhibit food intake in mice when administered by peripheral injection (Turton, M. D., Nature 379:69-72, 1996; Bhavsar, S. P., Soc. Neurosci. Abstr. 21:460 (188.8), 1995).
The results of an investigation of whether exendins are the species homolog of mammalian GLP-1 was reported by Chen and Drucker who cloned the exendin gene from the Gila monster (J. Biol. Chem. 272(7):4108-15 (1997)). The observation that the Gila monster also has separate genes for proglucagons (from which GLP-1 is processed), that are more similar to mammalian proglucagon than exendin, indicates that exendins are not species homologs of GLP-1.
Agents that serve to delay gastric emptying have found a place in medicine as diagnostic aids in gastrointestinal radiological examinations. For example, glucagon is a polypeptide hormone that is produced by the alpha cells of the pancreatic islets of Langerhans. It is a hyperglycemic agent that mobilizes glucose by activating hepatic glycogenolysis. It can to a lesser extent stimulate the secretion of pancreatic insulin. Glucagon is used in the treatment of insulin-induced hypoglycemia, for example, when administration of glucose intravenously is not possible. However, as glucagon reduces the motility of the gastro-intestinal tract it is also used as a diagnostic aid in gastrointestinal radiological examinations. Glucagon has also been used in several studies to treat various painful gastrointestinal disorders associated with spasm. Daniel, et al. (Br. Med. J., 3:720, 1974) reported quicker symptomatic relief of acute diverticulitis in patients treated with glucagon compared with those who had been treated with analgesics or antispasmodics. A review by Glauser, et al. (J. Am. Coll. Emergency Physns, 8:228, 1979) described relief of acute esophageal food obstruction following glucagon therapy. In another study, glucagon significantly relieved pain and tenderness in 21 patients with biliary tract disease compared with 22 patients treated with placebo (M. J. Stower, et al., Br. J. Surg., 69:591-2, 1982).
Methods for regulating gastrointestinal motility using amylin agonists are described in commonly owned
International Application No. PCT/US94/10225, published Mar. 16, 1995.
Methods for regulating gastrointestinal motility using exendin agonists are described in commonly owned U.S. patent application Ser. No. 08/908,867, filed Aug. 8, 1997 entitled “Methods for Regulating Gastrointestinal Motility,” which application is a continuation-in-part of U.S. patent application Ser. No. 08/694,954 filed Aug. 8, 1996.
Methods for reducing food intake using exendin agonists are described in commonly owned U.S. patent application Ser. No. 09/003,869, filed Jan. 7, 1998, entitled “Use of Exendin and Agonists Thereof for the Reduction of Food Intake,” which claims the benefit of U.S. Provisional Application No. 60/034,905 filed Jan. 7, 1997, No. 60/055,404 filed Aug. 7, 1997, No. 60/065,442 filed Nov. 14, 1997 and No. 60/066,029 filed Nov. 14, 1997.
Exendins have also been reported to have inotropic and diuretic effects, as set forth in commonly owned International Application No. PCT/US99/02554, filed Feb. 5, 1999, claiming the benefit of Provisional Application No. 60/075,122, filed Feb. 13, 1998.
Novel exendin agonist compounds are described in commonly owned PCT Application Serial No. PCT/US98/16387 filed Aug. 6, 1998, entitled “Novel Exendin Agonist Compounds,” which claims the benefit of U.S. patent application Ser. No. 60/055,404, filed Aug. 8, 1997.
Other novel exendin agonists are described in commonly owned PCT Application Serial No. PCT/US98/24210, filed Nov. 13, 1998, entitled “Novel Exendin Agonist Compounds,” which claims the benefit of U.S. Provisional Application No. 60/065,442 filed Nov. 14, 1997.
Still other novel exendin agonists are described in commonly owned PCT Application Serial No. PCT/US98/24273, filed Nov. 13, 1998, entitled “Novel Exendin Agonist Compounds,” which claims the benefit of U.S. Provisional Application No. 60/066,029 filed Nov. 14, 1997.
Since the appearance of the first therapeutically active peptides and proteins produced by genetic engineering, there has been an ever-increasing demand to be able to deliver these drugs by routes other than parenteral. This has been thwarted, however, by the very properties of peptides and proteins that set them apart from the small drug molecules widely in use today. These properties include molecular size, susceptibility to proteolytic breakdown, rapid plasma clearance, peculiar dose-response curves, immunogenicity, biocompatibility, and the tendency of peptides and proteins to undergo aggregation, adsorption, and denaturation.
It is generally understood that the administration of peptide drugs by routes other than subcutaneous or intravenous injection, or intravenous infusion, is often not practical because of, for example, in the case of oral administration, both enzymatic degradation and non-absorption in the gastrointestinal tract. Thus, there continues to exist a need for the development of alternative methods to the inconvenient, sometimes painful, injection for administration of peptide drugs, such as exendins and the peptide exendin agonist analogs referenced above. In addition to formulations and dosages useful in the administration of exendins and exendin agonists by injection, formulations, dosage formulations, and methods that solve these problems and that are useful in the non-injection delivery of therapeutically effective amounts of exendin and exendin agonists are described and claimed herein.
The contents of the above-identified articles, patents, and patent applications, and all other documents mentioned or cited herein, are hereby incorporated by reference in their entirety. Applicants reserve the right to physically incorporate into this application any and all materials and information from any such articles, patents, patent applications, or other documents mentioned or cited herein.